排序方式: 共有7条查询结果,搜索用时 15 毫秒
1
1.
Da Rocha AR Alves FR Neto NM Dos Santos LF De Almeida HM De Carvalho YK Bezerra Dde O Ferraz MS Pessoa GT De Carvalho MA 《Microscopy research and technique》2012,75(10):1376-1382
Stem cells are present in the adult tissues of most diverse species. Bone marrow is recognized to be the most exploited site to obtain stem cells and cell progenitors. The objective of the present study was to characterize hematopoietic progenitor (HP) morphology and analyze the performance of adherent cell progenitors (ACPs) cultivated in vitro from black‐rumped agouti bone marrow (Dasyprocta prymnolopha). Bone marrow aspirates were obtained from tibia crest and used to prepare histological slides and identify cell morphology. Cells were also scattered on culture plates for later isolation, expansion, and quantification. Smears obtained from bone marrow demonstrated HPs at different stages of maturity. In culture, these cells showed fibroblastoid morphology and a strong tendency to form colonies, demonstrated by the presence of cell aggregates, cytoplasmic elongations lying side by side. An 80% cell confluence was observed at 18 days in culture and progressive reduction in the percentage of nonadherent mononuclear cells. After eight passes, a mean cell viability of 96.07% was observed, from a pool of 1.6 × 107 cells (ACP). Thirteen 25‐cm2 culture bottles were trypsinized, resuspended in freezing medium, stored in 14 criotubes at a concentration of 1 × 106 cells per milliliter, and placed in liquid nitrogen at ?196°C. Agouti bone marrow demonstrated high plasticity, moreover different HP lines, and a population of adherent cells demonstrated morphology similar to mesenchymal stem cells in culture. Microsc. Res. Tech. 2012. © 2012 Wiley Periodicals, Inc. 相似文献
2.
The concentrations of V, Mn, Fe, Ni, Cu, Zn, As, Se, Mo, and Pb were measured in digestive gland (DG), branchial hearts (BH), gill (G), and muscle (M) of Octopus vulgaris Cuvier, 1797 caught in three fishing areas of the Portuguese coast, Viana do Castelo, Cascais, and Santa Luzia, for 2 years. The elemental concentrations measured for the different tissues were in accordance with values reported in the literature. The digestive gland presented high concentration levels of Fe, Cu, and Zn, while the branchial hearts showed elevated levels of V, Ni, Mo, as well as Fe and Cu. Significant variations in As, V, Cu, Mo, and Pb tissue concentrations were observed for animals originated from different sampling sites. Pb and As determined in the digestive gland and branchial hearts of animals from Cascais and Santa Luzia, can reflect local environmental characteristics. The variability observed in the elemental concentrations may be useful to further assess the species susceptibility to environmental conditions. 相似文献
3.
Summary Tetrachloro-dibenzo-dioxins
were declared as human carcinogenic substances in 1997. Objective: to analyse the scientific
production about tetrachloro-dibenzo-dioxins between 1976 and 2005. Solla Price
and Bradford models were applied. Different aspects of papers were analysed.
Impact factor of journals was studied. 3484 articles were found. The number of
articles published each year is fitted to Solla Price model. It has been shown
the scientific literature dispersion. Specialisation of some journals of Nucleus
and 1st Bradford Zone has been shown. 相似文献
4.
Cardoso-Martins Cláudia; Corrêa Marcela F.; Lemos Letícia S.; Napole?o Ricardo F. 《Canadian Metallurgical Quarterly》2006,98(3):628
Two longitudinal studies were conducted to investigate the development of Brazilian Portuguese-speaking children's ability to spell words in light of Ferreiro's and Ehri's models of spelling development. Twenty children participated in the 1st study. Their spelling skills were evaluated periodically from ages 4 to 6 years. The 124 children who participated in the 2nd study ranged from 4 to 7 years of age. They were tested twice, with an interval of approximately 6 months. The results suggest that Ehri's partial alphabetic phase offers a more parsimonious explanation of children's early understanding of the relationship between print and speech than does Ferreiro's syllabic stage. It is argued that syllabic spellings are more accurately depicted as an instance of partial alphabetic spellings. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
5.
Pontual EV Carvalho BE Bezerra RS Coelho LC Napoleão TH Paiva PM 《Food chemistry》2012,135(3):1848-1854
This work reports the detection and characterization of caseinolytic and milk-clotting activities from Moringa oleifera flowers. Proteins extracted from flowers were precipitated with 60% ammonium sulphate. Caseinolytic activity of the precipitated protein fraction (PP) was assessed using azocasein, as well as α(s)-, β- and κ-caseins as substrates. Milk-clotting activity was analysed using skim milk. The effects of heating (30-100°C) and pH (3.0-11.0) on enzyme activities were determined. Highest caseinolytic activity on azocasein was detected after previous incubation of PP at pH 4.0 and after heating at 50°C. Milk-clotting activity, detected only in the presence of CaCl(2), was highest at incubation of PP at pH 3.0 and remained stable up to 50°C. The pre-treatment of milk at 70°C resulted in highest clotting activity. Enzyme assays in presence of protease inhibitors indicated the presence of aspartic, cysteine, serine and metallo proteases. Aspartic proteases appear to be the main enzymes involved in milk-clotting activity. PP promoted extensive cleavage of κ-casein and low level of α(s)- and β-caseins hydrolysis. The milk-clotting activity indicates the application of M. oleifera flowers in dairy industry. 相似文献
6.
We apply atomistic simulations using the so called ‘metallic-covalent bonding’ interatomic model for the Fe–C system to study mobility of 〈1 0 0〉 interstitial dislocation loops, known to form in Fe and Fe-based ferritic alloys under irradiation, and their interaction with Carbon atoms. Carbon atoms represent an effective trap for the 〈1 0 0〉 loops with a binding energy of the order of 1 eV. The mobility of the loops is studied using the dislocation – loop drag model. From this model the activation parameters are identified and discussed. 相似文献
7.
Rolim LA Macêdo MF Sisenando HA Napoleão TH Felzenszwalb I Aiub CA Coelho LC Medeiros SR Paiva PM 《Journal of food science》2011,76(2):T53-T58
This article reports the genotoxicity assessment of an extract of M. oleifera seed powder and the water-soluble Moringa oleifera lectin (WSMoL) isolated from seeds. The lectin isolated by chitin chromatography showed hemagglutinating activity with different erythrocytes, activity in a broad pH range (4.5 to 9.5), and retention of hemagglutinating activity after being heated to 100 °C. Genotoxicity of the seed extract and WSMoL were assessed using the cell-free plasmid DNA as well as the Salmonella typhimurium (Ames and Kado) assays with TA97, TA98, TA100, and TA102 in the presence or absence of hepatic metabolization. Seed extract at concentration (0.2 μg/μL) recommended to treat water was not genotoxic by Ames, Kado, and cell-free plasmid DNA assays. S. typhimurium strains showed to be sensitive to M. oleifera extract revealing a mutagenic effect at doses higher than 0.6 μg/μL with hepatic metabolization. The extract at doses higher than 0.4 μg/μL, without hepatic metabolization, was mutagenic for TA100 and TA102. WSMoL was nonmutagenic by used assays. The use of high concentrations of the extract may pose a risk to human health and the safe use of M. oleifera seed powder to treat water for human consumption requires more study; however, the purified lectin could be an alternative for water treatment. PRACTICAL APPLICATION: The concentration 0.2 μg/μL of M. oleifera seed extract recommended to treat water for humans did not pose a risk to human health. The mutagenicity detected at concentrations higher than 0.4 μg/μL was not due to WSMoL, lectin isolated from extract. 相似文献
1